<PAGE>

                                                                     EXHIBIT 4.6

                     Nissan Auto Receivables Corporation II
                              990 West 190th Street
                           Torrance, California 90502

                                                       Dated as of June 24, 2004

                           YIELD SUPPLEMENT AGREEMENT

Wells Fargo Bank, National Association
Wells Fargo Center
Sixth and Marquette Avenue
MAC N9311-161
Minneapolis, MN 55479
Attn:  Asset Backed Securities Department

Nissan Auto Receivables 2004-B Owner Trust
In care of: Wilmington Trust Company
Rodney Square North
1100 North Market Street
Wilmington, DE 19890
Attn: Nissan Auto Receivables 2004-B Owner Trust

Ladies and Gentlemen:

      Nissan Auto Receivables Corporation II (the "Company") hereby confirms
arrangements made as of the date hereof with you, Wells Fargo Bank, National
Association, as Indenture Trustee, and Wilmington Trust Company, as Owner
Trustee for the Nissan Auto Receivables 2004-B Owner Trust (the "Trust"), for
the benefit of the Noteholders, to be effective upon (i) receipt by the Company
of the enclosed copy of this letter agreement (the "Yield Supplement
Agreement"), executed by Nissan Motor Acceptance Corporation ("NMAC"), the
Indenture Trustee and the Owner Trustee, (ii) execution of the Purchase
Agreement, dated as of the date hereof (the "Purchase Agreement"), between the
Company and NMAC, (iii) receipt by NMAC of the payment by the Company of the
purchase price under the Purchase Agreement, and (iv) the receipt by the Company
of the capital contribution of NMAC in connection with the payment of the
purchase price under the Purchase Agreement. Capitalized terms used herein and
not otherwise defined herein shall have the respective meanings given to them in
the Sale and Servicing Agreement, dated as of the date hereof, among NMAC, as
Servicer, the Company, and Nissan Auto Receivables 2004-B Owner Trust, as Issuer
(the "Sale and Servicing Agreement").

      1.    On or prior to each Determination Date, the Servicer shall notify
the Company and the Owner Trustee of the "Yield Supplement Deposit" (as defined
below) for the related Distribution Date, the amount on deposit in the Yield
Supplement Account (as defined below), the Servicing Payment Deposit with
respect to the related Distribution Date and the amount of reinvestment income
during the related Collection Period on the Yield Supplement Account. The "Yield
Supplement Deposit" means, with respect to any Distribution Date, the amount by
which (i) the aggregate amount of interest that would have been due during the
related Collection Period on all Yield Supplemented Receivables (as defined
below) if such Yield Supplemented Receivables bore interest at the Required Rate
(as defined below) exceeds (ii) the amount of interest accrued on such Yield
Supplemented Receivables at their respective APRs and due during such Collection
Period. "Required Rate" means, with respect to each Collection Period, 5.21%.
"Yield Supplemented Receivable" means any Receivable that has an APR less than
the Required Rate.

      2.    On or before the date hereof, the Owner Trustee shall establish and
maintain with the Securities Intermediary and pledge to the Indenture Trustee a
segregated trust account in the name of the Indenture Trustee for the benefit of
the Noteholders (the "Yield Supplement Account") in accordance with the
Securities Account Control Agreement to secure the payment of interest on the
Notes, or such other account as may be acceptable to the Rating

                                                      (Nissan 2004-B Owner Trust
                                                     Yield Supplement Agreement)

<PAGE>

Agencies, and the Trust hereby grants to the Indenture Trustee for the benefit
of the Noteholders a first priority security interest in the Yield Supplement
Account and the monies on deposit and the other property that from time to time
comprise the Yield Supplement Account (including the Initial Yield Supplement
Amount), and any and all proceeds thereof (collectively, the "Yield Supplement
Account Property"). The Indenture Trustee shall possess all of the rights of a
secured party under the UCC with respect thereto. The Yield Supplement Account
Property and the Yield Supplement Account shall be under the sole dominion and
control of the Indenture Trustee. Neither the Company, the Trust nor any Person
claiming by, through or under the Company or the Trust shall have any right,
title or interest in, any control over the use of, or any right to withdraw from
amounts from, the Yield Supplement Account Property or the Yield Supplement
Account. All Yield Supplement Account Property in the Yield Supplement Account
shall be applied by the Relevant Trustee as specified in this Yield Supplement
Agreement and the Sale and Servicing Agreement. The Relevant Trustee shall, not
later than 5:00 P.M., New York City time on the Business Day preceding each
Distribution Date, withdraw from the Yield Supplement Account and deposit in the
Collection Account an amount equal to the Yield Supplement Deposit plus the
amount of reinvestment income on the Yield Supplement Account for such
Distribution Date.

      3.    On or prior to the date hereof, the Company shall make a capital
contribution to the Trust of $82,748,552.58 (the "Initial Yield Supplement
Amount"), by depositing such amount into the Yield Supplement Account. The
amount required to be on deposit in the Yield Supplement Account on the date of
issuance of the Notes and for each Distribution Date until the Notes of all
Classes have been paid in full or the Indenture is otherwise terminated (the
"Required Yield Supplement Amount"), as determined by the Servicer and notified
to the Relevant Trustee, means an amount equal to the lesser of (i) the
aggregate amount of each Yield Supplement Deposit that will become due on each
future Distribution Date, assuming that payments on the Receivables are made on
their scheduled due dates, no Receivable becomes a prepaid Receivable and a
discount rate of 1.00%, and (ii) the Initial Yield Supplement Amount. The
Required Yield Supplement Amount may decline as a result of prepayments or
repayments in full of the Receivables. The Relevant Trustee shall have no duty
or liability to determine the Required Yield Supplement Amount and may fully
rely on the determination thereof by the Servicer. If, on any Distribution Date,
the funds in the Yield Supplement Account are in excess of the Required Yield
Supplement Amount for such Distribution Date after giving effect to all
distributions to be made on such Distribution Date, the Relevant Trustee shall
deposit the amount of such excess into the Collection Account for distribution
by the Relevant Trustee in accordance with the terms of Sections 5.06(c), (d),
(e) and (h) of the Sale and Servicing Agreement. The Yield Supplement Account
shall be part of the Trust. It is the intent of the parties that the Yield
Supplement Account Property be treated as property of the Trust for all federal,
state and local income and franchise tax purposes. The provisions of this Yield
Supplement Agreement should be interpreted accordingly. Further, the Trust shall
include in its gross income all income earned on the Yield Supplement Account
Property and the Yield Supplement Account.

      4.    All or a portion of the Yield Supplement Account may be invested and
reinvested in the manner specified in Section 5.08 of the Sale and Servicing
Agreement in accordance with written instructions from the Servicer or the
Secured Party (as defined in the Securities Account Control Agreement) under the
Securities Account Control Agreement, as the case may be. All such investments
shall be made in the name of the Relevant Trustee. Earnings on investment of
funds in the Yield Supplement Account shall be deposited in the Collection
Account on each Distribution Date, and losses and any investment expenses shall
be charged against the funds on deposit therein. Upon payment in full of the
Notes under the Indenture, as directed in writing by the Servicer, the Indenture
Trustee will release any amounts remaining on deposit in the Yield Supplement
Account to the Owner Trustee for the benefit of the Certificateholders, which
amounts the Owner Trustee shall deposit into the Trust Collection Account, and
the Company shall have no further obligation to pay to the Servicer the
Servicing Payment Deposit. If for any reason the Yield Supplement Account is no
longer an Eligible Deposit Account, the Relevant Trustee shall promptly cause
the Yield Supplement Account to be moved to another institution or otherwise
changed so that the Yield Supplement Account becomes an Eligible Deposit
Account.

      5.    Our agreements set forth in this Yield Supplement Agreement are our
primary obligations and such obligations are irrevocable, absolute and
unconditional, shall not be subject to any counterclaim, setoff or defense
(other than full and strict compliance by us with our obligations hereunder) and
shall remain in full force and effect without regard to, and shall not be
released, discharged or in any way affected by, any circumstances or condition
whatsoever.

                                                      (Nissan 2004-B Owner Trust
                                       2             Yield Supplement Agreement)

<PAGE>

      6.    This Yield Supplement Agreement shall not be amended, modified or
terminated except in accordance with the provisions for amendments,
modifications and terminations of the Sale and Servicing Agreement as set forth
in Section 10.01 of the Sale and Servicing Agreement.

      7.    THIS YIELD SUPPLEMENT AGREEMENT SHALL BE GOVERNED BY, AND CONSTRUED
IN ACCORDANCE WITH, THE INTERNAL LAWS OF THE STATE OF NEW YORK, without
reference to its conflict of law provisions (other than Section 5-1401 of the
General Obligations Law of the State of New York), AND THE OBLIGATIONS, RIGHTS
AND REMEDIES OF THE PARTIES UNDER THIS AGREEMENT SHALL BE DETERMINED IN
ACCORDANCE WITH SUCH LAWS.

      8.    Except as otherwise provided herein, all notices pursuant to this
Yield Supplement Agreement shall be in writing, personally delivered, sent by
telecopier, sent by courier or mailed by certified mail, return receipt
requested, and shall be effective upon receipt thereof. All notices shall be
directed as set forth below, or to such other address or telecopy number or to
the attention of such other person as the relevant party shall have designated
for such purpose in a written notice.

            The Company:

            Nissan Auto Receivables Corporation II
            990 West 190th Street
            Torrance, California 90502
            Attention: Treasurer
            Facsimile No.: 310-324-2542

            Indenture Trustee:

            Wells Fargo Bank, National Association
            Wells Fargo Center
            Sixth and Marquette Avenue
            MAC N9311-161
            Minneapolis, MN 55479
            Attn: Asset Backed Securities Department
            Facsimile No.: 612-667-3464

            Trust:

            Nissan Auto Receivables 2004-B Owner Trust
            In care of: Wilmington Trust Company
            Rodney Square North
            1100 North Market Street
            Wilmington, DE 19890
            Attn: Nissan Auto Receivables 2004-B Owner Trust

      10.   This Yield Supplement Agreement may be executed in one or more
counterparts and by the different parties hereto on separate counterparts, all
of which shall be deemed to be one and the same document.

      11.   Each of the parties hereto agrees and acknowledges that all of the
rights and interests of the Indenture Trustee hereunder shall be automatically
transferred to the Owner Trustee, and the Owner Trustee shall succeed to all
such rights and interests, upon the payment in full of the Notes in accordance
with the terms of the Indenture and the Sale and Servicing Agreement.

      If the foregoing satisfactorily sets forth the terms and conditions of our
agreement, please indicate your acceptance thereof by signing in the space
provided below and returning to us the enclosed duplicate original of this
letter.

                                                      (Nissan 2004-B Owner Trust
                                       3             Yield Supplement Agreement)

<PAGE>

                                         Very truly yours,

                                         NISSAN AUTO RECEIVABLES CORPORATION II

                                         By: /s/ Joji Tagawa
                                             -----------------------------------
                                             Name: Joji Tagawa
                                             Title: Treasurer

Agreed and accepted as of June 24, 2004

NISSAN MOTOR ACCEPTANCE CORPORATION

By: /s/ Steven R. Lambert
    ----------------------------
     Name:  Steven R. Lambert
     Title: President

WELLS FARGO BANK, NATIONAL ASSOCIATION,
   AS INDENTURE TRUSTEE

By: /s/ Marianna C. Stershic
    ----------------------------
      Name:  Marianna C. Stershic
      Title: Vice President

NISSAN AUTO RECEIVABLES 2004-B OWNER TRUST

By: WILMINGTON TRUST COMPANY,
      not in its individual capacity but solely as
      Owner Trustee on behalf of the Trust

      By: /s/ Kathleen A. Pedelini
          ------------------------
           Name:  Kathleen A. Pedelini
           Title: Financial Services Officer

                                                      (Nissan 2004-B Owner Trust
                                       S-1           Yield Supplement Agreement)